1. Technical Field
The present disclosure relates to a video display device that displays a video, such as a moving image, and a video display method.
2. Description of the Related Art
Technologies in the field of projection mapping onto a moving object have been developed recently. It is known that if a video, such as a moving image, is projected onto a moving object, a gaze of a viewer who is watching the video moves, thus the displayed video is likely to cause a sense of discomfort because the viewer feels it is intermittent. To avoid such a sense of discomfort, in this technical field, there has been developed a technology of using a high-speed projection element, such as a digital micromirror device (DMD), to control a display pattern at high speed (for example, International Publication WO 2017/110086).
International Publication WO 2017/110086 discloses a high-speed display device that plays a moving image at high speed and with high gradation. For example, it is presumable that a moving image is projected at a frame rate of, for example, 1000 fps by creating gradation of a video by turning mirrors of a DMD ON/OFF in time division. However, in a case where a moving image is played on a moving body at such a high frame rate, the entire screen needs to be updated at the boundary between frames, and there is a limit on the number of gradations that can be created on one frame of, for example, a millisecond. Accordingly, the high-speed display device according to International Publication WO 2017/110086 represents a high-gradation image by distributing gradation values of the input image as varied gradation values to multiple frames and temporally changing as many gradation values as the number of low gradations in each frame. Accordingly, a high-speed video display to a certain degree of high gradation is achieved under various implementation restrictions such as a limit of a transmission and processing device.